I saw a Guy on Americas Funniest Home Videos do it. I thought it was funny. I really like the Paper Shred in the Vent idea. I would suggest Paper hole punches instead (Or Glitter). Those things are a pain to pick up. You could always hook it up to the lights.

get a temp control for an electric fan. set it somewhat low. when the car heats up it will click the relay and since it wont get that cold it will stay open. im sure you could run 2 relays in there to make it work.

get a temp control for an electric fan. set it somewhat low. when the car heats up it will click the relay and since it wont get that cold it will stay open. im sure you could run 2 relays in there to make it work.

meh, thats too much for just a prank, just loosen the lug nuts, sit back, and watch

Change the sound of his horn too. That'd be cool if every time the horn went off his car would yell something out. Or to scare the crap out of him, hook up a 3 piece set of Nathan air chimes/ or similar.

Drill a hole through the middle of a potato. Then jam a whistle in one end of the potatoe. Finally, shove that potatoe inside of your victim's car exhaust pipe. Make sure the whistle is facing the outside. When your victim starts the car up and drives off, he will keep hearing a whistle and wonder what is going on.

A friend of mine bought a a piece of shit talon for 200.00$ Took a washer bottle with pump ran lines to upper intake hooked toggle switch to said pump,filled washer bottle with trans fluid.Instant spy hunter smoke screen.

Cut a bike inner tube then tie one end off and hose clap it to the tail pipe throw it under the car. when he starts the car the exhaust will start filling the inner tube and somewhere down the road thinner tube will fill up and pop. Should scare the shit out of him, and more than likely he will stop to see what happen and when he see's the inner tube he will grab it to pull it off his tailpipe and burn his hands...

Wire an M-80 to a turn signal and place it behind the grill infront of the radiator. when he turns on the turn signal it should blow the grill out and bust the radiator at the same time....

A friend of mine took a junk window and broke it, then rolled down his buddies drivers side window and put the broken glass from the junk window around his car. The guy thought his car was broken into and used plastic for a window for 2 months in the middle of winter. He finally realized it wasn't broken when he took it to the shop to get it fixed.

I saw a Guy on Americas Funniest Home Videos do it. I thought it was funny. I really like the Paper Shred in the Vent idea. I would suggest Paper hole punches instead (Or Glitter). Those things are a pain to pick up. You could always hook it up to the lights.